Laccase immobilization on chitosan/poly(vinyl alcohol) composite nanofibrous membranes for 2,4-dichlorophenol removal

A novel method of laccase immobilization on electrospun chitosan/poly(vinyl alcohol) composite nanofibrous membranes was developed. Laccase from Trametes versicolor was immobilized on the membranes by glutaraldehyde crosslinking. Its physical, chemical, and biochemical properties, as well as its application in 2,4-dichlorophenol removal were investigated. Scanning electron microscopy and transmission electron microscopy images showed that the fiber diameters were 50-200 nm, and that the membranes were porous and continuous. The laccase loading on the membranes was about 853 mg/g under the optimum conditions (pH 4, 10 h). Compared with free laccase, immobilized laccase was less sensitive to changes in pH, temperature, and oscillation, thereby exhibiting higher stability and reusability. The catalytic performances of free and immobilized laccases were evaluated by the degradation of 2,4-dichlorophenol. The removal efficiency of 2,4-dichlorophenol by immobilized laccase was about 87.6% under the optimum conditions (pH 6, 50 degrees C) after 6 h, which was much higher than that of free laccase (82.7%). (C) 2013 Elsevier B.V. All rights reserved.